THE POISON GARDEN website

Pontifications on Poison

Being some ramblings on events associated with poisonous plants.

Wednesday 7th September 2011

One of my favourite radio programmes is BBC Radio 4’s ‘More
or Less’. I’m so interested in it that I have been known to
switch it off, because I couldn’t give it my full attention, and
listen to it later on the BBC website.

It is supposed to about numbers and how they are wrongly used
by people who don’t know any better or misused by people who
should. I put ‘supposed to be’ because an item on the latest
programme had only a tangential relationship to numbers but it
was very interesting.

Apparently, a recent report said that trials showed that
acupuncture was effective in reducing pain. The producers of
‘More or Less’ asked a doctor who blogs about the subject to
look at the stated results and see if the claimed improvements
could be justified. The first, and most important, thing the
doctor found was that there had been no control group during the
trial.

If you are doing a trial to see if a drug or procedure works
it is not enough to just give some people the procedure and
compare them to people who have not had it. You have to have a
group of people who are made to think they have had the
procedure. This is because an essential principle of measuring
things scientifically is to have only one variable. That is the
only way to be certain that what you are measuring or observing
is the result of the changes in that variable.

If you are testing a new drug, for example, it is easy to
make up one set of pills containing the substance under test and
a visually identical set made of all the same ingredients except
for the test substance. Obviously, if you are examining a
procedure rather than a drug the challenge is to find something
that seems to be the procedure but isn’t. This is not always
possible, for example, if you want to know if a surgical
intervention is effective it is hard to create the impression
that an operation has been performed.

With acupuncture, however, there are sham techniques that
give the subject the belief that they have had acupuncture even
though there is no penetration of the skin. There remains a
drawback to this, however, which is that you cannot make a trial
of acupuncture versus sham acupuncture double blind. Double
blinding means that the person dealing with the trial subject
does not know if that subject is having the actual test or is a
control. This helps to eliminate any inadvertent communication
to the subject that could tell them what they are receiving.

Clearly, there is no way for a person administering
acupuncture or sham acupuncture not to know which procedure they
are using. Nonetheless, having a control group receiving sham
acupuncture is essential if you want to claim that any observed
results are the result of the acupuncture and not the placebo
effect.

Cannabis sativa

Most people these days have heard of the placebo effect but a
lot still think of it as just some sort of magic. It may seem
like magic; the idea that people feel better in spite of not
being given any actual medicine or treatment does seem
inexplicable but, in fact, we do now have a pretty good
understanding of what can trigger a placebo effect even if it
remains hard to know why.

There have been trials showing that the way a medicine is
given can make a difference to its effects; subjects told to
‘try this’, when given a sugar pill, reported less benefit that
those given the same sugar pill but told ‘this has been very
successful with other people’. There have been trials showing
that simply taking an interest in someone’s condition without
any intervention of any sort can produce a reduction in
symptoms.

In spite of what has been claimed for acupuncture the largest
effect* seems to be a result of the attention paid to the
patient. If you go to your GP you get five minutes and, because
your history is known, that is all that is needed to prescribe a
remedy. If you go to an acupuncturist, they will spend quite a
while taking your history so that they know what treatment to
apply. Plus, of course, they are, usually, charging for their
service so they feel the need to be seen to give value for
money.

This last is one of the more worrying aspects of the placebo
effect. Trials have shown that people respond better to
expensive treatment. Subjects in one trial were treated
identically except that one group were told the ‘medication’ (a
sugar pill) was cheap and the other believed the pills to be
costly. I find the cost effect worrying because, if a way can be
found for doctors to harness the placebo effect without going
against their ethical requirement not to lie to patients, you
can’t be sure of getting the best effect from a free
consultation.

Urtica dioica, stinging nettle

Naturally, people who believe in things like homeopathy, are
reluctant to accept that it is all placebo effect. If they
believed the truth about homeopathic substances it could
diminish the placebo effect so I tend not to bother to argue
with them. I do, however, give them what to me is a telling
example of the placebo effect.

Some years ago, in the USA, a trial was sanctioned for a
substance derived from
Cannabis sativa thought to be useful in reducing the nausea
associated with chemotherapy. In trials, all the subjects are
warned about any possible side effects from the drug being
tested and, in this trial ‘getting high’ counted as a side
effect. One of the trial subjects pulled out early because he
said the medicine was making him high and he was not a drug type
person and he did not like the experience of intoxication from
cannabis. The trial records showed that he had been part of the
control group, in other words the substance that got him high
contained no cannabis whatever.

*I said ‘largest effect’ because I think there may be useful
things about acupuncture that are still to be discovered. Trials
conducted in Plymouth suggest that
Urtica dioica, stinging nettle, might produce a reduction in
pain though a great deal more work is needed to be sure it is
the stinging that is creating the effect. To my simple mind it seems possible that causing mild
pain, from nettles or needles, may cause the brain to wake up to
the more serious pain it has been ignoring.